Caster



M U A B A c CASTER Filed Nov. 1, 1944 2 Sheets-Sheet 1 gvwmvkw CHARLESR. BRO

Y y w c. A. BAUM 2,437,588"

CASTER Filed Nov. 1, 1944 2 Sheets-Sheet 2 Cunmxs A. Baum Show;

Patented Mar. 9, 1948 UNITED STATE S PATENT OFFICE 6 Claims. 1

This invention relates to casters and more particularly to casters fortrucks. or similar relatively heavy vehicles, furniture or otherequipment.

The general object of the invention is to provide a novel and improvedcaster of the type described which is simple and sturdy in construction,easy and economical to manufacture and assemble, and capable ofswivelling freely under load without jamming or locking.

A more particular object of the invention is the provision of a casterof this type which is dust proof and dirt proof, affording an advantageover casters now in general use which over a period of timebecomeclogged with dirt and grit which causes wear on the relatively movingparts and reduces the efiiciency of the caster.

Another object of the invention is to provide a caster which is usablein cast form, that is, without machining the parts. After casting, allof the parts are immediately ready for assembly as soon as the castinggates are removed.

A further object is the provision of a caster which swivels on rollerbearings, or rather on relatively large and flat bearing discs, thebearing elements and the cooperating bearing raceson the base plate andbody member being so constructed and proportioned that'the bearings,although not provided with spacers, cannot iam no matter what stress isapplied to the caster.

A still further specific object of the invention is to provide a novelcaster in which the relatively swivelling parts rotate in slidingcontact, and in which novel contacting surfaces are formed on both thebase plate and the swivelling body of the caster, so as to reduce wear,eliminate unnecessary friction, and cause the device to functionperfectly under heavy loads.

Other objects and features of novelty will be apparent from thefollowing specification when read in connection With the accompanyingdrawings in which certain embodiments of the invention are illustratedby way of example.

In the drawings:

Figure 1 is a view in vertical section of a caster embodying theprinciples of the invention;

Figure 2 is a view in end elevation of the same caster, the hub of thewheel being shown in section;

Figure 3 is a bottom plan view of the base plate of the caster which issecured to the truck or other body to which the caster is applied;

. 2 Figure 4 is a view in side elevation of the same member;

Figure 5 is a top plan view of the swivelling body member of the caster;

Figure 6 is a view in vertical section of a modified form of castercoming within the general scope of the present invention, and utilizesroller bearings as an anti-friction means; I

Figure 7 is an end view of this embodiment;

Figure 8 is a top plan view of the body portion or housing member of thecaster, with the roller bearings applied; and

Figure 9 is a view in side elevation of one of the tapered rollerbearings.

Referring now to Figures 1 to 5 inclusive illustrating one embodiment ofthe invention, it will be seen that the caster assembly comprisesessentially the base plate it, the body portion or housing member H, andthe supporting wheel l2. The plate [0 may be of any peripheralconfiguration but is preferably of the contour shown in Figure 3 havingfour ears i3 perforated as at id for the insertion of bolts or screws tosecure it firmly to the underside of the truck or other equipment orbody to which the caster is applied.

Centrally of the plate 10 there is provided 9. depending hollow boss orstem l5 above which there is formed a recess l8 which is separated fromthe central bore I1 01' the stem by means of the horizontal shoulder l8.

The swivelling housing or body portion ll of the caster has asubstantially cylindrical outer configuration at its upper portion 20and formed on this upper portion are the downwardly depending spacedarms 22. These arms are of course offset from the center of the casterso as to attain the swivelling action and are provided with bearingopenings 23 at their lower ends through which the axle 24 extends. Thewheel I2 is rotatably mounted upon the axle 24. Upon the outer faces ofthe depending arms 22 are formed the vertical ribs 25 each having a flatshoulder 28 formed at the lower end thereof. The axle 24 is provided ateach end with a head 28 which for the most part is of a sphericalconfiguration but is cut away along one chord to form a flat face 29adapted to contact with the adjacent shoulder 26 of a rib 25 when theaxle 24 is applied. This will eflectively prevent rotation of the axle.

The tire 33 of the axle I2 is preferably of a substantially sphericalcontour to aid in the swivelling action. The hub 35 of the wheel is of adoublejfrusto-conicei outer configur tion and is provided centrally witha chamber II for inbricating grease which is applied through the opening81 in the hub by means of a grease gun or other accessory,

The upper portion 2| of the swlvelling body member or housing II isprovidcd centrally with an opening it adapted to receive the lower endof the hollow boss or stem II which extends from the base plate It.outwardly of this central opening. an upwardly extending annular rib orflange 40 is formed which has inclined side walls. The extreme outerwall of the upper portion 20 and the swlvelling member Ii is comprisedchiefly by the outwardly extending annular flange ll concentric with theinner flange ll, having an inclined inner side wall 42 and being spacedfrom the inner flange It to provide an annular bearing pocket M. p Thebottom surface I! of the bearing pocket ll is tapered or inclined sothat its radially inner portion is slightly higher than the outerportion.

Embracing the outer rib or flange ii and depending from the base plateIt is the downwardly directed annular flange 41. This flange cooperateswith the flange II to provide a dust and dirt excluding means.

Also depending from the base plate i is the annular bearing rib orflange 50. This flange has a tapered bottom surface ll of complementaryconfiguration to the tapered surface I! of the bearing recess M, and thesurface II is interrupted at intervals by the gaps or intervals 52 asclearly shown in Figures 3 and 4 of the drawings. This arrangementserves to reduce the bearing surface to the minimum required to supp rtthe load.

I A rivet 55 is inserted through the opening ll in the plate l0 and thelower head 58 of the rivet overlies the margins of the opening 38 in thehousing member I i. Theupper end of the rivet is headed over andbears-upon the shoulder I 8 of the plate and the two relativelyswlvelling parts are thus retained in assembled relationship even whenthe truck or member to which the caster is applied is lifted from thefloor.

In the embodiment illustrated in Figures 6 to 9 inclusive of thedrawings, the swlvelling or housing member i i and the wheel I! are ofexactly the same construction as the corresponding elements shown anddescribed in connection with the first embodiment and the parts will begiven the same reference numerals.

The plate H0 in this embodiment is furnished with ears H3 by means ofwhich it may-be secured to the truck or other equipment, and it isprovided centrally with-the depending hollow boss or stem H which entersthe central opening 38 of the member Ii and is connected with the latterby means of the bolt 55.

The plate H0 is also provided with the radially outwardly disposeddepending annular flange Ill which embraces the outer upwardly extendingouter flange I of the member II in dust excluding relationship.

The plate llli differs from the plate I 0 of the embodiment flrstdescribed in that, instead of the depending bearing flange 50, the plateis provided with an inclined or tapered bearing surface I50 which isdisposed opposite to and in complementary relationship with the inclinedbearing surface -or track 45 formed at the bottom of the pocket 44 ofthe member Ii. These bearing surfaces or tracks 45 and ISO are disposedin radially inwardly converging relationship and a plurality thesetracks and within the pocket 44. The roller bearing discs III aretaperedto lit the tracks ii and Ill and the lateral surfaces II! are ofa substantially spherical shape.

in order to reduce the friction of the swlvelling movement the rollerbearing discs III are made as large aspracticable and are as few innumber as can effectively serve the purpose. In the embodimentillustrated. eight of these roller bearing discs are shown and'the ratioof the mean diameter of the roller bearing discs to the mean diameter ofthe tracks 4| and I It is in the neighborhood of approximately one tothree. Of course. within the scope of the invention, the number ofbearing discs and these diameter ratios may be varied to some extentwithout danger of Jamming or producing excess friction. For example, thenumber of bearing discs may well vary from say six to twelve, and therelative dimension of the diameters accordingly, maintaining the spacingof the discs within reasonable limits. Such permissible variations wouldbring the disc-to-track diameter ratios roughly within the limits of 1:8 to 1:8. The inclined faces I42 of the inner walls of the pocket 4|serving to guide the rollers by contact with the spherical end surfacesof the discs.

Preferably, all of the parts are cast in final finished form without thenecessity of machining, the only requirement being to remove the castinggates before assembly. Alternatively, the parts may be made of malleableiron or mechanite metal.

Various changes and modifications may be made in the embodimentsillustrated and described herein without departing from the scope of theinvention as defined by the following claims.

Having thus described the invention what is claimed as new and desiredto be secured by Letters Patent is:

1. A caster of the class described comprising in combination a plateadapted to be secured to atruck or the like, a depending substantiallycentrally disposed stem carried by said plate, a swlvelling housingmember having a caster wheel rotatably mounted thereon, said housingmember being provided with a central opening to receive said stem with asnug bearing flt, this radial bearing between said stem and said housingmember being the sole radial bearing of said caster,

means for securing said housing member and said stem rotatably together,two concentric annular flanges formed on said housing member, projectingupwardly therefrom, and spaced apart to provide between them an annularpocket having substantially smooth uninterrupted side walls, the bottomof said pocket comprising an annular radially inclined uninterruptedtrack the radially inner side of the track being higher than the outer,the cross-section of said pocket being at least as deep as it is wide anannular downwardly projecting flange on said plate adapted to enclosethe outer of the two flanges on the housing member- 'truck or the like,a depending substantially centrally disposed stem carried by said plate,a swivelling housing member having a caster wheel rotatably mountedthereon, said housing member being provided with a central opening toreceive of tapered bearing discs Iii are disposed between 76 said stemwith a snug bearing fit, this radial bearbeing the sole radial bearingor said caster, means for securing said housing member and said stemrotatably together, two concentric annular flanges formed on saidhousing member, projecting upwardly therefrom, and spaced apart toprovide between them an annular pocket, having substantially smoothuninterrupted side walls, the bottom of said pocket comprising anannular radially inclined uninterrupted track, the radially inner sideof the track being higher than the outer, the cross section of saidpocket being at least as deep as it is wide an annular downwardlyprojecting flange on said plate adapted to enclose the outer of the twoflanges on the housing member to exclude dust and the like, a dependingannular flange formed on said plate inwardly of said dust excludingflange and having its lower edge hearing on said track to provide thrustbearing means between said plate and said housing member, said lastnamed flange being free of contact laterally with the inner walls ofsaid two first named concentric flanges.

3. A caster of the class described comprising in combination a plateadapted to be secured to a truck or the like, a depending substantiallycentrally disposed stem carried by said plate, a swivelling housingmember having a caster wheel rotatably mounted thereon, said housingmember being provided with a central opening to receive said stem with asnug bearing flt, this radial bearing between said stem and said housingmember being the sole radial bearing of said caster, means for securingsaid housing member and said stem rotatably together, two concentricannular flanges formed on said housing member, projecting upwardlytherefrom, and spaced apart to provide between them an annular pocket,having substantially smooth uninterrupted side walls, the bottom of saidpocket comprising an annular radially inclined uninterrupted track, theradially inner side of the track being higher than the outer, the crosssection 01 said pocket being at least as deep as it is wide, an annulardownwardly projecting flange on said plate adapted to enclose the outerof the two flanges on thehousing member to exclude dust and the like, adepending antrally disposed stem carried by said plate, a

swivelling housing member having a caster wheel rotatably mountedthereon, said housing member being provided with a central opening toreceive said stem with a snug bearing 111;, this radial bearing betweensaid stem and said housing member being the sole radial bearing of saidcaster, means for securing said housing member and said stern rotatablytogether, two concentric annular flanges formed on said housing member,projecting upwardly therefrom, and spaced apart to provide between theman annular pocket of a depth greater than its width, and havingsubstantially smooth uninterrupted side walls, the bottom of said pocketcomprising an annular radially inclined uninterrupted track, theradially inner side of the track being higher than the outer, an annulardownwardly projecting flange on said plate adapted to enclose the outerof the two flanges on the housing member to exclude dust and the like,an annular radially inclined track formed on said plate and disposedabove and in spaced relation-- ship to the track on the housing member,a plurality of flat. somewhat Irusto-conical bearing discs disposedbetween said tracks and guided between the concentric flanges on thehousing member, the inner walls of said pocket being upwardly divergentand the end walls of said bearings being of a substantially sphericalcontour.

5. A caster as set forth in claim 4 in which the diameter of each of thebearing discs is approximately twice the width thereof.

6. A caster of the class described comprising in combination a plateadapted to be secured to a truck or the like, 9. depending substantiallycentrally disposed stem carried by said plate, a swivelling housingmember having a caster wheel rotatably mounted thereon, said housingmember being provided with a central opening to receive said stem with asnug bearing flt, this radial bearing between said stem and said housingmember being the sole radial bearing of said caster, means for securingsaid housing member and said. stem rotatably together, two concentricannular flanges formed on said housing member, projecting upwardlytherefrom, and spaced apart to provide between them an annular pocket ofa depth greater than its width, an annular radially inclined trackformed on said housing member at the bottom of said pocket, the radiallyinner side of the track being higher than the outer, an annulardownwardly projecting flange on said plate adapted to enclose the outerof the two flanges on the housing member to exclude dust and the g like,an annular radiall inclined track formed on said plate and disposedabove and in spaced 1 relationship to the track on the housing member,

- nular flange formed on said plate inwardly of a plurality of flat.somewhat frusto-conical hearing discs disposed between said tracks andguided between the. concentric flanges on the housing member, thediameters of said bearing discs being or the order or from aboutone-eighth to about one-third of the mean diameter of the track.

CHARLES A. BAUM.

REFERENCES CITED The tollowing reterences are of record in the flle ofthis patent:

unrrnn STATES PATENTS 1,711,723 D Cousins May 'I, 1929

